From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48921) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gPp12-0003bz-8W for qemu-devel@nongnu.org; Thu, 22 Nov 2018 08:27:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gPp0u-0007Oi-0w for qemu-devel@nongnu.org; Thu, 22 Nov 2018 08:27:30 -0500 Received: from 9.mo7.mail-out.ovh.net ([46.105.60.248]:40327) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gPp0t-0007Ck-QO for qemu-devel@nongnu.org; Thu, 22 Nov 2018 08:27:23 -0500 Received: from player691.ha.ovh.net (unknown [10.109.143.146]) by mo7.mail-out.ovh.net (Postfix) with ESMTP id 585BAE9461 for ; Thu, 22 Nov 2018 14:27:17 +0100 (CET) Date: Thu, 22 Nov 2018 14:27:08 +0100 From: Greg Kurz Message-ID: <20181122142708.510f2f69@bahia.lan> In-Reply-To: <1542892767-37213-1-git-send-email-spopovyc@redhat.com> References: <1542892767-37213-1-git-send-email-spopovyc@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Qemu-ppc] [PATCH for 3.1 v3] spapr: Fix ibm, max-associativity-domains property number of nodes List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Serhii Popovych Cc: qemu-ppc@nongnu.org, lvivier@redhat.com, qemu-devel@nongnu.org, david@gibson.dropbear.id.au On Thu, 22 Nov 2018 08:19:27 -0500 Serhii Popovych wrote: > Laurent Vivier reported off by one with maximum number of NUMA nodes > provided by qemu-kvm being less by one than required according to > description of "ibm,max-associativity-domains" property in LoPAPR. > > It appears that I incorrectly treated LoPAPR description of this > property assuming it provides last valid domain (NUMA node here) > instead of maximum number of domains. > > ### Before hot-add > > (qemu) info numa > 3 nodes > node 0 cpus: 0 > node 0 size: 0 MB > node 0 plugged: 0 MB > node 1 cpus: > node 1 size: 1024 MB > node 1 plugged: 0 MB > node 2 cpus: > node 2 size: 0 MB > node 2 plugged: 0 MB > > $ numactl -H > available: 2 nodes (0-1) > node 0 cpus: 0 > node 0 size: 0 MB > node 0 free: 0 MB > node 1 cpus: > node 1 size: 999 MB > node 1 free: 658 MB > node distances: > node 0 1 > 0: 10 40 > 1: 40 10 > > ### Hot-add > > (qemu) object_add memory-backend-ram,id=mem0,size=1G > (qemu) device_add pc-dimm,id=dimm1,memdev=mem0,node=2 > (qemu) [ 87.704898] pseries-hotplug-mem: Attempting to hot-add 4 ... > > [ 87.705128] lpar: Attempting to resize HPT to shift 21 > ... > > ### After hot-add > > (qemu) info numa > 3 nodes > node 0 cpus: 0 > node 0 size: 0 MB > node 0 plugged: 0 MB > node 1 cpus: > node 1 size: 1024 MB > node 1 plugged: 0 MB > node 2 cpus: > node 2 size: 1024 MB > node 2 plugged: 1024 MB > > $ numactl -H > available: 2 nodes (0-1) > ^^^^^^^^^^^^^^^^^^^^^^^^ > Still only two nodes (and memory hot-added to node 0 below) > node 0 cpus: 0 > node 0 size: 1024 MB > node 0 free: 1021 MB > node 1 cpus: > node 1 size: 999 MB > node 1 free: 658 MB > node distances: > node 0 1 > 0: 10 40 > 1: 40 10 > > After fix applied numactl(8) reports 3 nodes available and memory > plugged into node 2 as expected. > > From David Gibson: > ------------------ > Qemu makes a distinction between "non NUMA" (nb_numa_nodes == 0) and > "NUMA with one node" (nb_numa_nodes == 1). But from a PAPR guests's > point of view these are equivalent. I don't want to present two > different cases to the guest when we don't need to, so even though the > guest can handle it, I'd prefer we put a '1' here for both the > nb_numa_nodes == 0 and nb_numa_nodes == 1 case. > > This consolidates everything discussed previously on mailing list. > > Fixes: da9f80fbad21 ("spapr: Add ibm,max-associativity-domains property") > Reported-by: Laurent Vivier > Signed-off-by: Serhii Popovych > --- Reviewed-by: Greg Kurz > hw/ppc/spapr.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c > index 7afd1a1..2ee7201 100644 > --- a/hw/ppc/spapr.c > +++ b/hw/ppc/spapr.c > @@ -1033,7 +1033,7 @@ static void spapr_dt_rtas(sPAPRMachineState *spapr, void *fdt) > cpu_to_be32(0), > cpu_to_be32(0), > cpu_to_be32(0), > - cpu_to_be32(nb_numa_nodes ? nb_numa_nodes - 1 : 0), > + cpu_to_be32(nb_numa_nodes ? nb_numa_nodes : 1), > }; > > _FDT(rtas = fdt_add_subnode(fdt, 0, "rtas"));